Fearless Butler confident of slaying 'Monster' Inoue in Japan
WBO champion Butler will attempt to do what no other boxer who has faced Inoue has managed so far - beat one of the sport's best pound-for-pound fighters and take his WBC, WBA and IBF belts.
"Monster" Inoue has won all his 23 fights, 20 by knockout, and became the first Japanese boxer to top The Ring magazine's pound-for-pound rankings as the best fighter across all weight divisions earlier this year.
Butler (34-2 with 15 KOs) said he was not daunted by the prospect of facing Inoue on home turf and was happy with his preparations after making the weight on Monday.
"He's a man - he's a man with two arms and legs," the 34-year-old Englishman told AFP.
"What he does in the ring is what he does, but I fear no one. It's a thing I'm looking forward to, getting in there and challenging myself."
The winner of Tuesday's bout will become the first undisputed bantamweight world champion since the four-belt era began in 2004.
"It's a massive achievement so it would mean a lot," said Butler.
"It would mean a lot to do it in front of my fans who have all travelled to Japan. It would be a great accomplishment."
Inoue failed to make weight on his first attempt, before returning minutes later and squeezing in under the 118-pound limit.
The 29-year-old shrugged off the misstep and said he remained laser-focused on completing his bantamweight title collection with Butler's WBO belt.
"I have lots of different strategies and I'll get into the ring and then I'll decide how to play it on instinct," Inoue said.
"Butler's tactics are by and large quite fixed, but nothing is pre-decided with my boxing. I'll decide how to attack after I face up to him."
